The invention relates to a vehicle stability control apparatus, which calculates the desired yaw rate from the exerted force on the vehicle or the generating physical quantity on the vehicle and executes feedback control so as to have the actual yaw rate correspond to the desired yaw rate. Particularly, this invention is applicable to an apparatus that can execute the feedback control such as a four wheel steer apparatus which steers individually both of the front wheels and the rear wheels, a limited slip differential control apparatus which controls the engagement power between front wheels and rear wheels or between right and left wheels, a braking force control apparatus, a stabilizer control apparatus or an active control suspension apparatus which is capable of adjusting the rolling rigidity.
As one example, Japanese Patent Kokai No. 9-2316 discloses a vehicle stability control apparatus that calculates a desired yaw rate from the angle of the steering wheel and the vehicle's velocity, and always executes control so as to have the actual yaw rate correspond to the desired yaw rate. With such conventional apparatus, when the vehicle is quickly turned so as to change lanes for emergency evasion on a low friction road such as an icy road, the feedback control is executed so as to make the actual yaw rate correspond to the desired yaw rate. However, the actual yaw rate cannot be accurately corresponded to the desired yawing moment without delay because the tires can not generate lateral force, braking force and traction force transmitted on a road. Accordingly, a delay of phase of the vehicle's yaw rate becomes large in comparison to a driver's steering operation when the vehicle is converging on straight-ahead driving, and driver tends to over-correct the vehicle's behavior.